Determining the identities of pieces of different steels



Patented Nov. 18, 1941' UNITED STATES PATENT OFFICE.

DETERIVIINING THE IDENTITIES OF PIECES OF DIFFERENT STEELS Herbert H.Schneider, East Cleveland, Ohio, assignor to The American Steel and WireCompany or New Jersey, a corporation of New Jersey No Drawing.

Application March 20, 1939,

I SerialNo. 263,058 2 Claims. (Cl. 73-51) The problem is particularlyacute when stocks of SAE 1035 and SAE 1335 steels become mixed.Therefore, the principles of the invention are hereinafter discussed asapplied to the solution of this particular situation.

According to the invention, sample portions of the two SAE steelsmentioned are heated to temperatures at least equaling the highest ofthe lower heating critical temperatures of the two steels, this beingthe SAE 1035 steel having'an AC1 temperature of 1340 degrees F. Thevarious portions are then cdoled in a furnace maintained at atemperaturelower than the highestof the lower cooling critical temperatures of thesteels and at least equaling the lowest of the lower cooling criticaltemperatures of the two steels,

this being the SAE 1335 steel having an Ari tem that from whichthe-portions are quenched, and

the SAE 1035 steel has a higher lower cooling critical temperature, itfollows that the former steel will be hardened while the latter willnot. Therefore, testing of the various portions to determine whetherthey hardened during the quenching provides a means for determiningtheir identities.

As the invention is now practiced, small sample pieces of the mixedstock of the two steels are heated in an ordinary rivet heating machinefor approximately twenty seconds, which is sufficient to heat them totemperatures above the highest of the upper heating criticaltemperatures of the two steels, this being the SAE 1035 steel having anAc: temperature of 1475 degrees F. The pieces are then quickly placed ina muflie furnace maintained at approximately 1200 degrees F. for asufiicient length of time for the pieces to reach this temperature, thisnormally taking only a, few minutes, whereupon the pieces are quenched.Upon testing for hardness, the

SAE 1035 steel will have a Brinell hardness in the neighborhood of 160,while theSAE 1335 steel will run from 400 to 500. Obviously, thisprovides a very easy means for identifying the various pieces and forconsequently permitting accurate rearrangement of the stock-for betterstorage or shipment.

Although the quenched pieces are described as being tested for Brinellhardness, it is possible to obtain reasonably accurate results by merelytesting the quenched pieces with a file. In all cases the mixed piecesof the different steels can be identified much more economically andrapidly than when the .prior art procedure is resorted to.

I claim:

1. A-method of determining the identities of mixed pieces of SAE 1035and SAE 1335 steels to permit their classification in separate groups,saidmethod including heating sample portions of said pieces totemperatures above the highest of the upper critical temperatures ofsaid steels, cooling said portions in a furnace maintained at atemperature lower than said highest critical temperature and at least ashigh as the lowest critical temperature of said steels, quenching saidportions, testing said portions to whether they hardened during saidquenching and classifying saidpieces in separate groups according towhethersaid portions thereof were hardened. 1

Z. A method of determining the identities of mixed pieces of steelshaving different critical temperatures and of approximately the samecarbon "cbntents to permit their classification in separate groups, saidmethod including heating sampleportions of said pieces to temperaturesabove the highest of the upper critical temperatures of saidsteels/cooling said portions in a furnace maintained at a temperaturelower than said highest critical temperature and at least as high as thelowest critical temperature of said steels, quenching said portions,testing said portions to determine whether they hardened during saidquenching and classifying said pieces in separate groups according towhether said pordetermine

